1. Invasion history of Fucus evanescens C. Ag. in the Baltic Sea region and effects on the native biota

2. Ishavstång (Fucus evanescens) Blåstång (Fucus vesiculosus)

3. Spridning och etablering av ishavstång i Sverige Faktorer som påverkar etableringen Effekter på inhemska arter

4. Invasion history of Fucus evanescens C. Ag. in the Baltic Sea region and effects on the native biota

5. Biological invasions A geographical expansion of a species to an area it has previously not inhabited

6. Caulerpa taxifolia

7. Fucus evanescens Bladder-wrack (Fucus vesiculosus) 1 cm

8. Questions Paper I Wikström SA, von Wachenfeldt T & Kautsky L: Establishment of the exotic species Fucus evanescens C. Ag. (Phaeophyceae) in Öresund, Southern Sweden. (1) How has Fucus evanescens spread and established in Sweden? (2) Which factors influence the invasion success of F. evanescens? Paper II Wikström SA & Kautsky L: Effects of the invading brown alga Fucus evanescens on associated biota (3) Does the introduction affect the native biota?

9. Study area

10. (1) How has F. evanescens spread and established in Öresund? First documentation 1948 (harbour of Copenhagen) Distribution and abundance of F. evanescens investigated 1966-72 and 2000 30 sites investigated (1) Pattern of spread

11. 1972 2000 (1) Pattern of spread

12. (2) Which factors influence the invasion success of F. evanescens? (2) Restricting factors F. evanescens mostly found - in northern Öresund - at sheltered sites (harbours) Salinity? Wave exposure?

13. (2) Restricting factors Salinity

14. (2) Restricting factors Salinity

15. (2) Restricting factors Salinity

16. Wave exposure (2) Restricting factors

17. Wave exposure Attachment strength - F. evanescens - F.vesiculosus - F. serratus (2) Restricting factors No difference

18. (2) Which factors influence the invasion success of F. evanescens? Wave exposure?No Salinity?Probably in southern Öresund Competition? (2) Restricting factors

19. (3) Associated epibiota (3) Does the introduction of F. evanescens affect the native biota? Does the epiphytic and epifaunal community of F. evanescens differ from that of the native F. vesiculosus? ?

20. (3) Associated epibiota Biomass Species number 14 7 Epiphytes

21. (3) Associated epibiota Epiphytes Infauna

22. (3) Does the introduction of F. evanescens affect the native biota? Fucus evanescens has - fewer epiphytic species - less epiphytic biomass - less biomass of motile fauna (3) Associated epibiota Does F. evanescens replace F. vesiculosus?

24. Thanks to… My supervisors Lena Kautsky and Ove Eriksson and all people who have contributed with field and laboratory assistance, statistical advice and scientific discussions. My family for their support. Stockholm Marine Research Centre (SMF) provided financial support.

27. Why important?

28. Wave exposure (2) Restricting factors

29. Detrended correspondence analysis (DCA) (3) Associated epibiota